1. Field of the Invention
The present invention relates to a complex circuit board comprising an electrode clasped between a dielectric substrate and a magnetic substrate, a nonreciprocal circuit device, a resonator, a filter, a duplexer, a communications device, a circuit module, a method for manufacturing the complex circuit board, and a method for manufacturing the nonreciprocal circuit device.
2. Description of the Related Art
Conventionally, dielectric substrates or magnetic substrates having electrode patterns thereon, forming a capacitance element and/or an inductance element, for example, have been laminated in multiple stages to form a resonator circuit or the like. Depending on the application and desired characteristics and the like, low-profiling is sometimes required, and a conventional complex circuit board has been devised to satisfy such requirements.
A conventional complex circuit board will be explained based on FIGS. 23 and 24. FIG. 23 is a plan view of a conventional complex circuit board, and FIG. 24 is a cross-sectional view taken along the line W—W of FIG. 23.
As shown in FIGS. 23 and 24, the conventional complex circuit board 110 comprises a dielectric substrate 111, a magnetic substrate 112, and an electrode pattern 120 clasped therebetween. The electrode pattern 120 comprises a capacitance element 121, an inductance element 122, a transmission line 123, and the like, and ground electrodes 113 are provided on the outer faces of the dielectric substrate 111 and the magnetic substrate 112. The complex circuit board 110 of this constitution functions here as a low-pass filter.
In the conventional complex circuit board 110, the electrode pattern 120 is provided by using plating or the like to form electrode 120a and 120b facing each other on the dielectric substrate 111 and the magnetic substrate 112, respectively, and by providing a connection electrode 120c thereabove. The electrode pattern 120 is completed by affixing together the electrode 120a and 120b respectively provided on the dielectric substrate 111 and the magnetic substrate 112, with the connection electrode 120c therebetween.
The characteristics of the capacitance element, the inductance element, resistors, transmission lines, and the like, which are provided on the complex circuit board, alter according to their positional relationships to the dielectric substrate and the magnetic substrate. For instance, the inductance element achieves a greater inductance when it is near to the magnetic substrate. Moreover, when the inductance element is near to the magnetic substrate, it can be miniaturized while obtaining the same inductance. similarly, the capacitance element achieves a greater capacitance when it is near to the dielectric substrate, and it can be miniaturized while still obtaining the same capacitance.
However, in the conventional complex circuit board, since the electrode pattern clasped between the dielectric substrate and the magnetic substrate is formed by affixing together electrodes provided on the dielectric substrate and the magnetic substrate, the entire electrode pattern lies within a single plane. That is, the capacitance element, the inductance element, the resistors, the transmission lines, and the like are disposed all at an equal distance from the dielectric substrate and from the magnetic substrate.
Furthermore, although the inductance element obtains a larger inductance when it is provided nearer to the magnetic substrate, its inductance is lowered when a dielectric substrate is nearby, because the coupling of the inductance element to the dielectric becomes stronger.
Furthermore, in the case of a distributed constant nonreciprocal circuit device, for instance, the electrode comprises a resonator portion and a transmission line portion, and the nonreciprocity of the device when a dc magnetic field is applied thereto is increased by providing the resonator portion near to the magnetic substrate. However, when a dielectric substrate is provided nearby, the coupling of the resonator portion to the dielectric is strengthened, lowering the nonreciprocity of the device.
Therefore, when the capacitance element, the inductance element, and the like formed by the electrode pattern, clasped between the dielectric substrate and the magnetic substrate, are provided within a single plane, there are disadvantages that the inductance can be increased only by a limited value, the elements cannot be miniaturized, and consequently the complex circuit board cannot be miniaturized. There is an additional disadvantage that it is not possible to precisely design the characteristics of the capacitance element, the inductance element, the resistor, the transmission lines, and the like.